In beverage distribution systems and particularly those used for beer, a pressure source is connected to the keg of beer by a flexible hose through a tapping mechanism which provides a means for securing the hose to the keg and also allowing dispensing of beer from the keg under the pressure provided from the source. Safety devices have been employed in beverage installations of this kind to control the amount of pressure delivered to the keg. Otherwise, should a rupture occur somewhere upstream of the keg tapping mechanism, the keg itself may become overpressurized to such an extent that it could very well explode or at least blow portions of the keg tapping mechanism with such force as to cause catastrophic consequences to those in the area of the keg. Safety devices used for this purpose have typically been mechanically adjustable and employed moving mechanical devices which are subject to frequent failure and blockage.
For adjustable safety devices the most common technique has been the use of a spring bias release valve with various adjusting devices. There have also been attempts to incorporate safety relief valves in the pressure reducing regulator to control pressure delivered from the source. However, these are also adjusted by anyone with the screw driver, pliers or other similar tool. Such adjustments are not unusual when employing such regulators because they allow for the variation of pressure being delivered to the kegs to satisfy the type of beverage and amount of gas which should be incorporated in the beverage as it is dispensed. Unfortunately, the use of these adjustable regulators allow even a well-intentioned operator to adjust the regulator in a manner which cancels the effect of any safety mechanism. For example, where the operator will hear the hissing noise that occurs when gas pressure begins being vented from the safety relief valve, and, knowing that this involves a gas leakage, may adjust the safety relief valve to stop the leakage. In doing so, the relief valve may be bottomed out completely invalidating its existence or use.
Other approaches have included the installation of safety relief valves in the keg or other beverage container itself. This has not proved to be completely satisfactory. By installing the relief valve inside the beverage container, it is continually exposed to the beverage product being dispensed from that container. As these products are by their very nature sticky, they adversely affect the predictability of the valves with which the beverage comes in contact. In other words, as the sticky beverage material permeates the interstices of the valve mechanism, elements of the mechanism may become adhered to one another to such an extent that it will not work properly, if at all.
Another problem with the use of a relief valve inside the beverage container relates to damage which can occur in the normal transportation, loading and unloading of the kegs. As they are dropped into containers, the forces resulting from the impact in this loading and unloading can cause surge pressures which exceed the normal safe limit of the container. This results in actuation of the safety device, allowing the beverage product to spill onto the floor of the truck body, sidewalks, etc., unnecessarily.
With regard to the spring bias relief valve system generally used in the connection apparatus, they are also subject to the major disadvantage of their constant exposure to the beverage itself. As mentioned above, the beverage is sticky and as it dries, it forms a reasonably effective glue which causes the lifting or actuating pressure of the valve itself to vary widely. Because of this variation, the spring bias release system is one which is found to be unreliable and unsafe.
Another major disadvantage is that these safety valves are normally incorporated into some other component element of the dispensing system. They are usually employed with the coupler body of the coupler device which is used to plumb the beverage container to the dispensing hoses and faucets. Because of the limitations in space and costs imposed on these systems, it is necessary that the safety system also be sufficiently small to work within the coupler. As a result of this size limitation, the safety valves may not provide an adequately large orifice through which to expel the excessive gases being applied from an overpressured or malfunctioning gas pressure regulator.
The pressure systems used with beverage distribution systems may require a source of up to over 1000 pounds per square inch. This, of course, varies substantially with temperature, but the normal pressure involved is usually around 800 pounds per square inch. If the reducing regulator on the gas cylinder should fail, allowing full bottle or source pressure to vent itself and to normal gas pressure feedline, it will achieve flow rates of and exceeding 60-100 cubic feet per minute. The size of the expulsion orifice in the existing safety relief valves are so small that they will not achieve the same flow rate at the same source pressure. More importantly, the upper safe limit of the keg pressure, which is much lower than the source pressure, will achieve a limited flow rate of only 17-21 standard cubic feet per minute. In other words, if they are not glued shut by the beverage residue and they lift at the proper pressure, they will not provide sufficient flow rate to safely vent the system. Their proper actuation merely delays the explosive rupture of the beverage container some fraction of a second or perhaps two seconds at the most, depending on whether the container is completely filled or partially filled with the beverage at the time of failure.
Other shortcomings involved with the use of a spring biased or adjustable pressure release valve include the restricted cavities which normally characterize such devices. This may cause contamination of the beverage passage itself.
As a matter of industry practice, these devices have always had an external protrusion which can be gripped to open the device against preset spring pressure to test its actuation or to remove whatever restriction may exist in the valve seat. Protruding as they do, these devices can be mechanically and physically blocked from actuation by contact with any other physical object with which it is placed in contact.
Because the beverage containers are placed within coolers and other storage places, the possibility of there being a blockage for the safety valve is one that is not a remote risk. In fact, in some coolers, the six packs of beverage cans or bottles, packages of meat, vegetables, and other products are frequently refrigerated in restaurant environments and placed on or adjacent these valve mechanisms in such a way that they block or prevent their actuation.
It is generally an object of the subject invention to overcome many of the deficiencies which have existed with the prior art devices discussed above. More particularly, it is an object of the invention to arrive at a safety device for use between a pressure source and a pressurized container from which the beverage is dispensed. The safety device described herein is one which, regardless of its installation, will work properly and can readily and easily be replaced after it has functioned.
Another object of the invention is to arrive at a safety device which cannot be disassembled without being destroyed in order to preclude the possibility of a well-intentioned operator to cancel the safety mechanism.
It is another object of the invention to arrive at a safety valve, which, if it malfunctions, malfunctions in a safe direction. That is, it will readily allow pressurized gas to pass through the valve without pressurizing the container carrying the beverage downstream of the valve.
It is another object of the invention to arrive at a safety valve incorporating a rupture disc, where there is a communication between the surface of the rupture disc and the atmosphere. However, such communication is not one which allows access to the rupture disc by operators using or installing the safety device, thereby impeding inadvertent damage of the device.
It is is still another object of the invention described herein to arrive at a safety device employing a rupture disc which does not require separation or parting of the hose of feedline system. In other words, the rupture disc can rupture, depressurizing the system, while a connection is maintained between the source and the beverage container.
It is still a further object of the invention to produce a safety valve which, when actuated, cannot be corrected in any other way except by total replacement. In this way, it is practically impossible to reuse a valve which is already ruptured.